The present invention relates to laser cutting installations in which the sheet is loaded automatically.
Laser cutting machines are now widely employed for processing of sheet metal workpieces since the laser will cut the sheet metal rapidly and the laser beam and/or the workpiece can be moved by a guidance system to enable precise cutting of parts. One type of common laser cutting machine for processing large sheet metal workpieces has a work support over which there is a movable bridge, and the laser cutting head is supported on the bridge. The bridge can be moved along the workpiece support to effect cutting of the workpiece in the longitudinal direction, and the laser cutting head can be moved along the bridge to effect cutting in the transverse direction. Illustrative of such machines is Erlenmaier U.S. Pat. No. 6,586,706 and Kilian U.S. Pat. No. 5,304,773.
Loading units for the sheet metal workpieces have been widely employed for punch presses and laser cutting machines and generally involve suction devices which are arranged in a grid that can be adapted to the size of the sheet metal workpiece to be picked up and carried by the loading unit. Generally, such loading units will pick up the sheet metal and then rotate or otherwise move to deposit the sheet on the workpiece support in the desired position. Exemplary of such loading units is that illustrated and described in Leibinger et al U.S. Pat. No. 6,066,531.
The cutting operation will frequently produce numerous small parts and a skeleton which must be removed from the workpiece support. Although the operator may remove and sort them manually, this extends the processing time and reduces the productivity of the laser cutting machine. Accordingly, various types of units have also been provided for removing from the workpiece support the cut parts and skeleton. It has also been proposed to leave small webs of material retaining the cut parts in the skeleton so that the cut workpiece can be lifted as a unit by a suction arrangement; the remaining webs are then broken to release the parts from the skeleton after it has been transported to a separation station.
It will be appreciated that these types of installations involve separate units with their own drive mechanisms. A numeric control system must not only control the cutting motion but also the motion of the loading unit and the unloading unit as the case may be. At times this presents problems from the standpoint of effecting the desired alignment of the workpiece in the workstation or rapid changes between different cutting programs.
It is an object of the present invention to provide a novel laser cutting installation in which cutting, loading and unloading units are provided in one single integrated machine.
It is also an object to provide such a laser cutting installation which can be fabricated relatively readily and which is simple to operate.